Morphologically controlled synthesis of Cu₂O nanocrystals and their properties

The ability to prepare inorganic nanocrystals with well-defined morphologies and sharp faces should facilitate the examination of their facet-dependent surface, catalytic, electrical, and other properties. In this review we cover different synthetic methods for the growth of Cu₂O nanocrystals with morphological control. Cu₂O nanocrystals with cubic, cuboctahedral, truncated octahedral, octahedral, and multipod structures have been prepared mainly by wet chemical, electrodeposition, and solvothermal synthesis methods. Methods used for the formation of hollow Cu₂O nanocubes, octahedra, and truncated rhombic dodecahedra are also presented. Morphology of Cu₂O nanocrystals can be expanded with the use of gold nanocrystal cores to guide the overgrowth of Cu₂O shells. Surface properties of Cu₂O nano- and microcrystals with sharp faces have been examined in a few studies. The {1 1 1} faces were found to interact well with negatively charged molecules, while the {1 0 0} faces are less sensitive to molecular charges. Preferential adsorption of sodium dodecyl sulfate molecules on the {1 1 1} faces of Cu₂O crystals has been demonstrated via plane-selective deposition of gold nanoparticles on only the {1 0 0} faces. It is expected that the development of improved synthetic methods for Cu ₂O nanocrystals and more knowledge of their facet-dependent properties should lead to their applications in photoactivated energy conversion and catalysis.